- obey exif orientation tag
- added Comment
- Thumbnail generation also obeys exif tag
- moved rotateImage() to BitmapUtils
Merge remote-tracking branch 'upstream/develop' into rotateImage

Conflicts:
	src/com/owncloud/android/datamodel/ThumbnailsCacheManager.java
Fixed. App crashes when previewing an image
Remove unused imports and split long lines modified
Cancel load task when fragment becomes invisible (fixes crash in rotations)
Hurry up release of source bitmap in rotations
Merge branch 'develop' into community_rotateImage
Merge pull request #799 from owncloud/community_rotateImage

Rotate image according to EXIF attributes.